1. Technical Field
This invention relates to a method for alleviating the condition of spinal canal stenosis by local administration of a medicine.
2. Description of the Related Art
The respective vertebral bodies ranging from the cervical to sacral spines and internal spaces surrounded by spinous processes are called spinal canal. The spinal canal stenosis means a condition wherein the spinal canal is narrowed such as by the hypertrophic degeneration of the spine making up of the spinal canal and the yellow ligament or by intervertebral disc protrusion, so that the nerve tissues of a nerve root, cauda equine and the like are compressed, thereby causing a variety of symptoms. This spinal canal stenosis may occur ascribed to naturally aged apophysis or from a degenerative disease or condition, or may sometimes occur with the case of a patient who suffers morbid obesity or a patient who takes peroral corticosteroids. Depending on the narrowed (or constricted) site of the spinal canal, the spinal canal stenosis can be classified into cervical spinal canal stenosis, thoracic spinal canal stenosis, lumbar spinal canal stenosis and extensive spinal canal stenosis. As these symptoms, mention is made of low back pain, or upper-extremity or lower-extremity pain or numbness resulting from nerve compression. Especially, if the cauda equinal nerve is damaged, the low back pain, or lower-extremity pain or numbness, or a feeling of weariness becomes severe during walking, and such a symptom is called intermittent claudication.
The treatment method of the spinal canal stenosis is fundamentally carried out according to a conservative medical management that generally, initially makes use of a drug therapy using an analgetic agent, an anti-inflammatory agent or the like, a gymnastic therapy for strengthening the abdominal and back muscles, a thermotherapy using a hot pack, an acupuncture treatment intended for pain relief effect, and an orthotic therapy fitting a corset.
Most of the spinal canal stenoses come to attention of the conservative medical management and many cases have been observed wherein stenotic symptoms are improved by a combination of various conservative therapies. However, a therapeutic medicine that has been accepted for a medical treatment of the spinal canal stenosis is only a prostaglandin E1 derivative preparation intended for an improvement of circulation in nervous system. Although this prostaglandin E1 derivative preparation is now commercially available for oral and intravenous uses, it cannot be said that both are effective against severe spinal canal stenosis involving intermittent claudication. This is considered for the reason that because of systemic administration, the local blood circulation at a stenotic site cannot be effectively improved. Such systemic administration involves such side effects to promote hemorrhage of patients having bleeding disorders such as, for example, intracranial bleeding, gastrointestinal bleeding, blood spitting and the like. A full recovery with the help of the conservative medical therapy is rare and such a therapy has often ended up in vain.
Especially, with the case of severely ill patients, decompressive laminectomy wherein the patients are subjected to spinal and nerve root decompressions is carried out. In this therapy, the back and muscles are cut open to remove the support structure from the backbone thereby exposing a rear face of the spine, followed by removing the vertebral arch portion covering the back side of the spinal canal to expose a thickened yellow ligament (laminectomy). Subsequently, the ligament of the thickened yellow ligament is removed. This treatment is carried out under general anesthesia. The patient generally needs to be hospitalized over about five to seven days depending on the age and general conditions of the patient, and it should take six weeks to three months before recovery from the treatment. Additionally, most of the patients have to be extended in treatment at rehabilitation facility so as to regain enough motion to live alone, thereby imposing a substantial burden on patient.
As set out above, in spite of the fact that the spinal canal stenosis causes many distressing symptoms on the part of patient, effective treatments and symptom-alleviating methods have never been established yet.